Harpen, N. H. v., & Watkins, S. J. (1930). The electrometric determination of the hydrogen ion concentration in the latex of Hevea brasiliensis and its applicability to technical problems. Varekamp & Co.
Chicago-viite (17. p.)Harpen, Nicolaas Hendrik van, ja S. J. Watkins. The Electrometric Determination of the Hydrogen Ion Concentration in the Latex of Hevea Brasiliensis and Its Applicability to Technical Problems. Medan: Varekamp & Co, 1930.
MLA-viite (8. p.)Harpen, Nicolaas Hendrik van, ja S. J. Watkins. The Electrometric Determination of the Hydrogen Ion Concentration in the Latex of Hevea Brasiliensis and Its Applicability to Technical Problems. Varekamp & Co, 1930.
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